4r70w question

[1966halfcab]

I am doing a 96 explorer engine and trans swap into my 76 Bronco. My question Is the ZF adapter from AA the way to go ? If so will I have to do any modifications to the driveshaft or crossmember ? It is mostly a street driven truck any help would be appreciated

 

[Boss Hugg]

I caught the 4r70w/d20 adapter on sale for Christmas a couple years ago. So I can't tell you how the ZF adapter works.

So, all in all... here's a bump for you.

 

[EricLar80]

The ZF adapter is a little cheaper because you use the existing transfer case adapter that comes with the 4r70w transmission. But it adds length to the system compared to the one that adapts directly. I chose to use the direct adapter because the transmission is already longer than a C4 and so the rear driveshaft gets pretty short and steep if you combine the added length from both the 4r70w and ZF.

Either case will require some cross member updates; they aren't that difficult to modify or make.

 

[1966halfcab]

So you would recommend the adapter like the one wild horses sells for roughly $525 over the ZF adapter correct ? I am looking for the best adapter with the least amount of modifications I don't really care too much about the cost

 

[EricLar80]

Yes, but I think it is $625. I specifically used advance adapters P/N 50-2704. I think this is the one you are talking about, right?
https://www.wildhorses4x4.com/product/Ford-AODE-4R70W-to-Dana-20-Adapter-converter/Bronco_Transmission_Adapters

Here is my thread to see specifically what I did:
http://classicbroncos.com/forums/showthread.php?t=167240

The nice thing about the ZF adapter is that you don't have to take the transmission apart to install the shaft, so it is cheaper and easier overall. But the drawback is that it is longer overall.

 

[Broncobowsher]

Have to start by asking if you got the all wheel drive version of the Explorer. Because that is the only way to run the ZF adaptor.
If you have a 2WD version, you will need a kit with a new output shaft and tail housing. Same kit also works on the AWD/4WD versions. The difference in the transmissions between 2WD and 4WD is the tailhousing and tailshaft.

Personally I like the tailhousing and output shaft conversion better. Less parts stacked and less tolerance stack up to sorry about.

This will push the transfer case back about 3" You will have to modify the crossmember or make a new one. This also changes the driveshaft lengths. The speedometer cable is usually long enough to reach.

 

[pcf_mark]

If you have not committed to the D20 then I suggest the NP205 swap. You can buy these used for $150, put in new gaskets for $20 and have an almost indestructible transfer case that bolts right up to the 4R70W. No need to take the transmission apart. You have to make a new trans mount and driveshafts with either swap.

 

[1966halfcab]

I really appreciate all the information, I am still undecided on which transmission to go with. Also my explorer is all wheel drive. Thanks again

 

[Boss Hugg]

I'll add one more thing. I started with a 2wd transmission. I'm not sure which kit I used, but it came with a 27 spline tailshaft to be installed in the Transmission. I am now considering adding a 2nd transfer case for a doubler (Cold duck d20), but if I had used the 4wd version, and done the zf adapter, I could use a homemade planetary type gear reduction box like the blackbox or strongbox. Just something else to consider based on your expected use of the truck.

 

[Viperwolf1]

There are 3 adapters that can be used. The one with the new output shaft will work on 2wd or awd. It's the shortest but is about $100 more than the one that doesn't include the output shaft. This one only works with awd. The ZF adapter requires use of the stock adapter and awd output shaft. I'm not sure about tcase shifter availability with this setup.

I have installed 3 or 4 of the high dollar adapters and am not very impressed with the aa output shaft. It's smaller than the stock awd shaft and has fewer splines.

 

[Broncobowsher]

The smaller 27 spline shaft is plenty for a 5.0 Explorer engine. I ran that on a pretty healthy 351 and was never worried about it.

 

[EricLar80]

I would venture to guess that the output shaft on the transfer case is a weaker link and the shaft between the trans and the transfer case. Particularly because it is loaded at an angle.

 

[sanndmann3]

If you have not committed to the D20 then I suggest the NP205 swap. You can buy these used for $150, put in new gaskets for $20 and have an almost indestructible transfer case that bolts right up to the 4R70W. No need to take the transmission apart. You have to make a new trans mount and driveshafts with either swap.

Yep. That is what I did after breaking 3 20s... Internals of the 205 are SO much beefier! only downside is low range gearing...